Exploring the Top PDF Watermarking APIs

When it comes to PDF Watermarking APIs, there are different options out there: In this post, we will compare some of the top APIs that we tried.
Exploring the Top PDF Watermarking APIs
Sohail Pathan
Last updated on October 31, 2023


PDF watermarking APIs allow users to add watermarks to PDF Documents, enhancing brand recognition and increasing security. More benefits of using watermarks include:
  • Deter unauthorized use
  • Prevent copyright infringement
  • Brand promotion
  • Establish authenticity
  Watermark on PDF
Watermark on PDF
In this article, we will explore and compare some of the most popular watermarking APIs.

Features & Functionality

Input Format

ApyHub allows you to provide source input in both Text and Image to watermark a PDF. Similarly, PDFRest, iLovePDF and PSPDFKit also allow you to provide source input in both Text and Image. PDF-Watermark-CTA.png
  Text watermark (left) & image watermark (right) in a PDF
Text watermark (left) & image watermark (right) in a PDF


Whether it's an image watermark or a text watermark, proper alignment and positioning are important in order to ensure that the message of the image is not disrupted. ApyHub offers additional parameter options, such as the watermark's position, rotation angle, opacity, and size. PSPDFKit also allows for some customization, for Dimension, Font, Opacity, Text Color, Text Size, Rotation, Font Style. PDFRest allows you to customize the Font, Opacity, Text Color, Text Size, Rotation, and Offset. iLovePDF allows you to customize Pages, Opacity, Position, Mosaic, Rotation, Font and Text Color.
pdfRest API Documentation Example
pdfRest API Documentation Example

SDKs and Client Libraries

ApyHub provides the client code in 8 languages (C, C#, JavaScript, Go, NodeJS, Java, Python, and PHP) and SDKs in Node.js and Go. iLovePDF provides SDKs in about 4 different languages, including PHP, Node.js, Ruby, Java and . NET. PSPDFKit offers developer guides in 5 languages including JavaScript, C#, Python, PHP and Java. PDFRest doesn’t seem to provide any SDKs.
  PSPDFKit Documentation Page
PSPDFKit Documentation Page.

Documentation and Tutorials

Apyhub APIs are supported with thorough documentation, including the Authentication method, Error Codes, HTTP Response Codes, and Request Examples. CloudConvert also has rich language-specific documentation but does not include an error and response code. Bannerbear has universal documentation for the developers. Api.video has provided documentation in the form of step by step guide which is easily understandable.

API Testing

Most of the providers let you test the APIs right from a terminal in the platform. ApyHub also has an API Playground where you can test the APIs in the UI plus you can see the snippet of the provided input in cURL. pdfRest offers a really rich API Lab for developers.
iLovePDF and PSPDFKit don’t seem to have any API Playground, although they provide you with cURL to test APIs in tools Postman/Hopscotch.
  PDFRest API Lab


ApyHub has served *99.99% of uptime. PSPDFKit, iLovePDF, and pdfRest also claim to have high uptime.


This is subject to change but at the time of writing, all providers offer a subscription-based tiered model including a free plan. The most generous free plan is from ApyHub, offering 2 Million API calls per month for free, PSPDFKit offers 100 calls per month, iLovePDF offers free 250 API Calls Per Month and pdfRest offers 300 API Calls per month.

Community Support

Most of the providers offer dedicated channels such as Discord, Slack, or Chatbot Agent to their users to ask support questions. ApyHub has a dedicated Discord Server, which lets you interact directly with the support team in addition to email support. Whereas PSPDFKit, iLovePDF and pdfRest have email-based support.
Below is a summary of the comparison of the providers I looked at.
Provider# Calls (Free)Input FormatCustomizationFile SizePricing ( Paid )Throttling
ApyHubUpto 2M calls in the free planImage & TextOpacity, Font Size, Angle50 MBStarting from 10 EUR/month. Custom pricing plan for Enterprises.1 call/s in the free plan
PSPDFKit100 Calls Per MonthImage & TextDimension, Font, Opacity, Text Color, Text Size, Rotation, Font Style5 MBStarting from 73 EUR/month.1 call/in the free plan
PDFRest300 Calls per MonthImage & TextFont, Opacity, Text Color, Text Size, Rotation, Offset2 MBStarting from 8 EUR/month.1 call/s in the free plan
iLovePDF250 Calls per MonthImage & TextPages, Opacity, Position, Mosaic, Rotation, Font, Text Color1 GBStarting from 38 EUR/month1 call/in the free plan


While all the providers offer PDF watermarking APIs, each has its own strengths and weaknesses. Ultimately, the best API for your specific requirements will depend on factors such as the level of customization needed, developer support, and budget constraints. We recommend exploring each provider's offerings in more detail to determine the best fit for your needs.
This is the third article I wrote on the subject of watermarking. Read here to see my comparison of the top Image-Watermarking-CTA2png.png and TOP-Video-Watermarking-CTA3.png
Do you agree with our list of the above API Providers? What do you think is the best watermarking API? Let us know your thoughts in the comments below.
*Disclaimer: This article is for informational purposes only. The opinions expressed are solely based on the research and may vary based on individual experiences and preferences.